Despite a lead actor whose voice has finally dropped an octave, the series of “Wimpy Kid” films has yet to crack its own prepubescent streak, with this year’s “Diary of a Wimpy Kid: Dog Days” dealing as much with the ritual humiliation of middle-class middle-schooler Greg (Zachary Gordon) as the last two entries have.

Cobbled together from episodes spread across the third and fourth books of Jeff Kinney’s popular franchise, “Dog Days” mostly sees Greg’s plans to spend his entire summer zoned out in front of a video game sabotaged by Dad (Steve Zahn) and his forced efforts to properly bond with the middle child of the Heffley clan. The threat of a stern prep school in his future prompts Greg to do what Greg does best (or, at least, most often): he lies.

Specifically, he lies about taking some responsibility and getting a job at the local country club, where he’s actually shown up as the guest of best friend Rowley (Robert Capron) to stalk his crush, Holly (Peyton List). Privilege abuse, pool-based embarrassment and tennis court silliness ensue, not to mention the involvement of Greg’s pushy older brother, Rodrick (Devon Bostick), and his infatuation with Holly’s own prissy sister.

But wait! There’s more! In keeping with the slapdash directorial tradition of the previous films (David Bowers also helmed last year’s “Rodrick Rules”), we jump back and forth between so many other half-hearted threads that it can feel a bit like surfing between channels that strictly show episodes of a never-made “Wimpy Kid” TV show. Dad gets the family a dog! Rowley’s family invites Greg on a vacation and proves to be surprisingly sensitive! Mom starts a book club! Dad competes with the fellow leader of an ill-planned scouting trip!

Of course, many of these dilemmas would be remedied if Greg didn’t have such a propensity for outright fibbery, but if he didn't, we wouldn’t really have a movie. In turn, it’s a character trait that has consistently made our hapless lead difficult to care for. He’s not wimpy so much as callous and careless in his actions, setting off technological mishaps usually reserved for female characters on “The Newsroom” and asking a man who’s HOLDING CLEAN TOWELS to pass him some especially girly swim trunks after he loses his own at the country club pool.

The fact that Gordon has managed to make Greg even remotely sympathetic is to the young actor’s credit. More admirably exuberant are Bostick and Zahn. The former belts out punk-rock Beiber covers with no shortage of aplomb, while the latter -- dearly missed in the world of movies not named “Wimpy Kid” -- both matches the manic energy of the series with his frequent mugging and sells solemn lines to the effect of “How could you rack up $260 in smoothies?” like a champ.

While one wonders if Greg’s lying streak will eventually see him the subject of a “Shattered Glass”-like drama once the series reaches his college years, I have it on good authority that Steve Zahn is already pretty good at handling those kinds of things.

To read the country club antics between Greg and Rowley as something of a parallel for modern concerns over class struggles might be overthinking things a bit, but in a summer where even the dance movie sequel arguably had our economic divide in mind, it will at least give the parents something to do with their time. A bit harder to argue against is this entry’s addition of homophobic humor in its gag-inducing arsenal. Greg treats an early scene set in a locker room and public shower like he’s crossing a minefield; later, he can’t stand the thought of sharing a bed with his lifelong pal. Meanwhile, Rodrick freaks out as a grown man proceeds to give him needless poolside CPR.

It’s a crutch on which the other films hardly, if ever, relied, more than happy to instead dole out the goofy, gooey nonsense that pleases the sub-teen set. All of that is here as well, but at this point, they stick out specifically as the kind of jokes that the summer’s family films (“Brave,” “Madagascar 3: Europe’s Most Wanted”) have generally, mercifully avoided so far. Alas, the grosses suggest that the gross-out factor has its place, and parents already indoctrinated by the likes of the “Wimpy Kid” franchise shouldn’t find themselves surprised by much of what “Dog Days” has to offer.